Journal articleApplied optics · October 2025
The introduction of scattering media along an imaging path typically results in a deterioration of image quality, as scattering re-directs light into off-axis trajectories. Our goal is to create an asymmetric vision environment by exacerbating this deterio ...
Full textCite
Journal articleRapid communications in mass spectrometry : RCM · May 2025
RationaleHigher resolution in fieldable mass spectrometers (MS) is desirable in space flight applications to enable resolving isobaric interferences at m/z < 60 u. Resolution in portable cycloidal MS coupled with array detectors could be improved ...
Full textCite
Journal articleInternational Journal of Mass Spectrometry · January 1, 2025
Mass spectrometers are essential instruments for in situ analysis of planetary materials. Ideally, a space flight mass spectrometer would have a mass range from ∼10 u to at least 500 u to enable analysis of organic molecules to aid in searching for the req ...
Full textCite
Journal articleApplied Optics · September 1, 2024
Given two aerosol plumes—one scattering and one absorbing—in the presence of a bright interferent, it has been shown that the image contrast ratio through the pair of plumes is different in the two opposing view directions [Appl. Opt. 54, 12 (2015)]. Here, ...
Full textCite
Journal articleAdvanced Functional Materials · July 17, 2024
The ultimate goal of this work is to create an engineered aerosol that acts as one-way smoke, i.e. it creates an asymmetric vision environment in which the ability to image objects depends on the viewing direction. To this end, a rapid, one-pot synthesis o ...
Full textCite
Journal articleNuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · July 1, 2024
In this work we describe how a novel mass spectrometer design we recently reported on can be utilized as an electron spectrometer having excellent resolution and passband width. This new electron spectrometer is referred to as a segmented electrode electro ...
Full textCite
Journal articleJournal of the American Society for Mass Spectrometry · May 2024
Spatial aperture coding is a technique used to improve throughput without sacrificing resolution both in optical spectroscopy and sector mass spectrometry (MS). Previous work demonstrated that aperture coding combined with a position-sensitive array detect ...
Full textCite
Journal articleJournal of mass spectrometry : JMS · July 2022
With the advent of technologies such as ion array detectors and high energy permanent magnet materials, there is renewed interest in the unique focusing properties of the cycloidal mass analyzer and its ability to enable small, high-resolution, and high-se ...
Full textCite
Journal articleAnalytical chemistry · August 2021
In 1938, Walker Bleakney and John A. Hipple first described the cycloidal mass analyzer as the only mass analyzer configuration capable of "perfect" ion focusing. Why has their geometry been largely neglected for many years and how might it earn a respecta ...
Full textCite
Journal articleJournal of the American Society for Mass Spectrometry · February 2021
Cycloidal sector mass analyzers have, in principle, perfect focusing due to perpendicularly oriented uniform electric and magnetic fields, making them ideal candidates for incorporation of spatially coded apertures. We have previously demonstrated a proof- ...
Full textCite
Journal articleInternational Journal of Mass Spectrometry · November 1, 2020
This work compares the coded aperture imaging performance of thermionic filament and carbon nanotube (CNT) field emitter-based electron sources in cycloidal-coded aperture mass spectrometers. The use of spatially coded apertures in mass spectrometry enable ...
Full textCite
Journal articleOptical Engineering · October 1, 2020
The resolution optimization and sampling strategies in practical digital in-line holography (DIH) with spherical wave illumination are analytically studied by optimizing system parameters. Optimal parameters of holographic recording, including illumination ...
Full textCite
Journal articleInternational Journal of Mass Spectrometry · September 1, 2020
Previous works experimentally demonstrated that the application of spatially-coded apertures to simple sector mass spectrographs can result in increased signal intensity while maintaining spectral resolution comparable to that of a conventional slit apertu ...
Full textCite
Journal articleOptica · July 20, 2019
BACKGROUND: Performing imaging with scattered light is challenging due to the complex and random modulation imposed upon the light by the scatterer. Persistent correlations, such as the optical memory effect (ME), enable high-fidelity, diffractionlimited i ...
Full textCite
Journal articleNuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms · June 15, 2019
Scatter-based X-ray imaging has increased in prominence in areas ranging from cancer diagnostics to threat detection in aviation security, due largely to the development of new algorithms and components over the last decade. However, system design and algo ...
Full textCite
Journal articleHongwai Yu Jiguang Gongcheng Infrared and Laser Engineering · April 25, 2019
The terahertz(THz) far-field radiation properties of a butterfly-shaped photoconductive antenna (PCA) were experimentally studied using a home-built THz time-domain spectroscopy(THz-TDS) setup. To distinguish the contribution of in -gap photocurrent and an ...
Full textCite
Journal articleJ Med Imaging (Bellingham) · April 2019
Anthropomorphic breast phantoms mimic patient anatomy in order to evaluate clinical mammography and digital breast tomosynthesis system performance. Our goal is to create a modular phantom with an anthropomorphic region to allow for improved lesion and cal ...
Full textLink to itemCite
Journal articleOptics letters · December 2018
Photoelastic modulator-based polarimeters use multi-carrier modulation schemes that are more complicated than the single carriers of rotating optics. Current state-of-the-art reconstruction implementations favor mathematical simplicity by using significant ...
Full textCite
Journal articleScientific reports · September 2018
Imaging through opaque scattering media is critically important in applications ranging from biological and astronomical imaging to metrology and security. While the random process of scattering in turbid media produces scattered light that appears uninfor ...
Full textCite
Journal articleJournal of the American Society for Mass Spectrometry · February 2018
Despite many potential applications, miniature mass spectrometers have had limited adoption in the field due to the tradeoff between throughput and resolution that limits their performance relative to laboratory instruments. Recently, a solution to this tr ...
Full textCite
Journal articleJournal of the American Society for Mass Spectrometry · February 2018
Cycloidal mass analyzers are unique sector mass analyzers as they exhibit perfect double focusing, making them ideal for incorporating spatial aperture coding, which can increase the throughput of a mass analyzer without affecting the resolving power. Howe ...
Full textCite
Journal articleApplied Physics Letters · January 22, 2018
The inpainting of deliberately and randomly sub-sampled images offers a potential means to image specimens at a high resolution and under extremely low-dose conditions (≤1 e-/Å2) using a scanning transmission electron microscope. We s ...
Full textCite
Journal articleNuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms · January 15, 2018
We present a pipeline that rapidly simulates X-ray transmission imaging for arbitrary system architectures using GPU-based ray-tracing techniques. The purpose of the pipeline is to enable statistical analysis of threat detection in the context of airline b ...
Full textCite
Journal articleAnnual review of analytical chemistry (Palo Alto, Calif.) · June 2017
The use of coded apertures in mass spectrometry can break the trade-off between throughput and resolution that has historically plagued conventional instruments. Despite their very early stage of development, coded apertures have been shown to increase thr ...
Full textCite
Journal articleOptics express · August 2016
Spectral imaging is a powerful tool for providing in situ material classification across a spatial scene. Typically, spectral imaging analyses are interested in classification, though often the classification is performed only after reconstruction of the s ...
Full textCite
Journal articleJournal of the American Society for Mass Spectrometry · April 2016
In order to minimize losses in signal intensity often present in mass spectrometry miniaturization efforts, we recently applied the principles of spatially coded apertures to magnetic sector mass spectrometry, thereby achieving increases in signal intensit ...
Full textCite
Journal articleJournal of the American Society for Mass Spectrometry · September 2015
Miniaturizing instruments for spectroscopic applications requires the designer to confront a tradeoff between instrument resolution and instrument throughput [and associated signal-to-background-ratio (SBR)]. This work demonstrates a solution to this trade ...
Full textCite
Journal articleApplied optics · March 2015
We investigate the utility of compressive sensing (CS) to electro-optic and infrared (EO/IR) applications. We introduce the field through a discussion of historical antecedents and the development of the modern CS framework. Basic economic arguments (in th ...
Full textCite
Journal articleJournal of the American Society for Mass Spectrometry · February 2015
In mass spectrometer design, there has been a historic belief that there exists a fundamental trade-off between instrument size, throughput, and resolution. When miniaturizing a traditional system, performance loss in either resolution or throughput would ...
Full textCite
Journal articleIEEE Transactions on Terahertz Science and Technology · January 1, 2015
Terahertz digital off-axis holography (THzDH) has been demonstrated as a non-destructive tool for imaging voids within visually opaque dielectrics. Using a raster scanning heterodyne detector, the imager captures lensless transmission holograms formed by t ...
Full textOpen AccessCite
Journal articleJournal of the American Society for Mass Spectrometry · July 2014
Conventionally, quadrupole ion trap mass spectrometers eject ions of different mass-to-charge ratio (m/z) in a sequential fashion by performing a scan of the rf trapping voltage amplitude. Due to the inherent sparsity of most mass spectra, the detector mea ...
Full textCite
Journal articleApplied optics · May 2014
System requirements for many military electro-optic and IR camera systems reflect the need for both wide-field-of-view situational awareness as well as high-resolution imaging for target identification. In this work we present a new imaging system architec ...
Full textCite
Journal articleOptics express · February 2014
Computer-generated volume holograms (CGVHs) are gradient refractive index (GRIN) devices that consist of a superposition of multiple periodic diffraction gratings. Fabrication of these components for the visible range is difficult due to the small length-s ...
Full textCite
Journal articleIEEE Transactions on Antennas and Propagation · January 1, 2014
Dielectric reflectarray antennas are proposed as a promising low-loss and low-cost solution for high gain terahertz (THz) antennas. Variable height dielectric elements are used in the reflectarray designs, which allow for the use of low dielectric-constant ...
Full textCite
Journal articleIEEE Transactions on Antennas and Propagation · January 1, 2014
In this work, we designed, built, and tested a low-gain 20 dBi Luneburg Lens antenna using a rapid prototyping machine as a proof of concept demonstrator. The required continuously varying relative permittivity profile was implemented by changing the size ...
Full textCite
Journal articleIEEE MTT S International Microwave Symposium Digest · December 1, 2013
A novel broadband electronically beam scanning structure based on Luneburg lens phased array is investigated in this paper. The radiation elements of the phased array are mounted on the surface of a Luneburg lens. Without amplitude and phase control of the ...
Full textCite
Journal articleInternational Conference on Infrared Millimeter and Terahertz Waves Irmmw Thz · December 1, 2013
Dielectric reflectarray antennas are proposed as a possible low-loss solution for high gain THz antennas. A 3-D printing technology is utilized to fabricate the antenna, and numerical and experimental results are presented for a prototype operating at 100 ...
Full textCite
Journal articleProceedings of the International Telemetering Conference · December 1, 2013
The AFSSI-C is a spectral imager that generates spectral classification directly, in fewer measurements than are required by traditional systems that measure the spectral datacube (which is later interpreted to make material classification). By utilizing a ...
Cite
Journal articleIEEE Antennas and Propagation Society AP S International Symposium Digest · December 1, 2013
Dielectric reflectarray antennas are studied in this paper as a possible low-loss and low-cost solution for high gain THz antennas. Variable height dielectric slabs are proposed for the reflectarray elements which allow for the use of low dielectric-consta ...
Full textCite
Journal articleProceedings of the International Telemetering Conference · December 1, 2013
Compressive Sensing (CS) is a set of techniques that can faithfully acquire a signal from sub- Nyquist measurements, provided the class of signals have certain broadly-applicable prop- erties. Reconstruction (or exploitation) of the signal from these sub-N ...
Cite
Journal article2013 7th European Conference on Antennas and Propagation Eucap 2013 · August 14, 2013
The design, fabrication and measured performance of an all-dielectric Terahertz (THz) horn antenna based on hollow-core electromagnetic crystal structure is described. Simulation result shows that the antenna works above 100 GHz, with better than 30 dB ret ...
Cite
Journal articleProceedings of SPIE the International Society for Optical Engineering · April 10, 2013
The monochromatic single frame pixel count of a camera is limited by diffraction to the space-bandwidth product, roughly the aperture area divided by the square of the wavelength. We have recently shown that it is possible to approach this limit using mult ...
Full textCite
Journal articleApplied optics · April 2013
The 2012 Computational Optical Sensing and Imaging (COSI) conference of the Optical Society of America was one of six colocated meetings composing the Imaging and Applied Optics Congress held in Monterey, California, 24-28 June. COSI, together with the Ima ...
Full textCite
Journal article2013 IEEE High Performance Extreme Computing Conference Hpec 2013 · January 1, 2013
We address certain properties that arise in gigapixel-scale image stitching for snapshot images captured with a novel micro-camera array system, AWARE-2. This system features a greatly extended field of view and high optical resolution, offering unique sen ...
Full textCite
Journal articleOptics InfoBase Conference Papers · January 1, 2013
We present the current development of the image formation pipeline for color gigapixel images obtained by the AWARE-10 multiscale camera.We introduce a camera simulator, the modifications to the scalable pipeline, and the challenges for creating seamless c ...
Cite
Journal articleOptics InfoBase Conference Papers · January 1, 2013
We describe the calibration challenges associated with a computational spectral imaging classifier and present initial experimental results. We also discuss planned system improvements to address these calibration challenges and observed performance issues ...
Cite
Journal articleIEEE Transactions on Antennas and Propagation · December 17, 2012
An all-dielectric terahertz (THz) horn antenna based on hollow-core electromagnetic crystal structure is designed, fabricated and characterized. Simulation shows that the antenna works above 100 GHz, with better than 30 dB return loss and highly directiona ...
Full textCite
Journal articleProceedings of SPIE the International Society for Optical Engineering · December 1, 2012
Traditional approaches to persistent surveillance generate prodigious amounts of data, stressing storage, communication, and analysis systems. As such, they are well suited for compressed sensing (CS) concepts. Existing demonstrations of compressive target ...
Full textCite
Journal articleProceedings of the International Telemetering Conference · December 1, 2012
A broadband passive direction finding system utilizing Luneburg lens has been investigated. With the simulated power level distribution at the detectors mounted on a Luneburg lens, both Cramér-Rao bound (CRB) and the root mean square error (RMS) based on t ...
Cite
Journal articleIEEE MTT S International Microwave Symposium Digest · October 3, 2012
In this paper, a 3-D Luneburg Lens is employed for direction finding application. Using the special property of a Luneburg lens that every point on the surface of the Lens is the focal point of a plane wave incident from the opposite side, a number of dete ...
Full textCite
Journal articleOptics express · September 2012
We report on the image formation pipeline developed to efficiently form gigapixel-scale imagery generated by the AWARE-2 multiscale camera. The AWARE-2 camera consists of 98 "microcameras" imaging through a shared spherical objective, covering a 120° x 50° ...
Full textCite
Journal articleOptics express · September 2012
This paper presents the Static Computational Optical Undersampled Tracker (SCOUT), an architecture for compressive motion tracking systems. The architecture uses compressive sensing techniques to track moving targets at significantly higher resolution than ...
Full textCite
Journal articleNature · June 2012
Pixel count is the ratio of the solid angle within a camera's field of view to the solid angle covered by a single detector element. Because the size of the smallest resolvable pixel is proportional to aperture diameter and the maximum field of view is sca ...
Full textCite
Journal articleComputational Optical Sensing and Imaging Cosi 2012 · January 1, 2012
We present our latest results in static compressive tracking and imaging. We have developed a design methodology using the compressed sensing concept of mutual coherence. We also elucidate a modified calibration scheme that boosts compressive imaging capab ...
Full textCite
Journal articleComputational Optical Sensing and Imaging Cosi 2012 · January 1, 2012
We have developed an architecture for spectral classification in spectral imaging. Adaptive kernels are designed using probabilistically-weighted principal component analysis. Simulation predicts orders-of-magnitude reduction in error rates, and a prototyp ...
Full textCite
Journal articleOptics Infobase Conference Papers · December 1, 2011
Advances in rapid prototyping technology have allowed for successful fabrication of terahertz computer-generated volume holograms. We report on our progress in the design, fabrication, and measurement of our first successful holograms. FIO/ LS Technical Di ...
Cite
Journal articleIrmmw Thz 2011 36th International Conference on Infrared Millimeter and Terahertz Waves · December 1, 2011
Terahertz all-dielectric Electromagnetic Crystal (EMXT) waveguide to planar microstrip line transition structures are designed, simulated and fabricated. The design is similar to the ridge coupling structure used in metallic waveguide to microstrip transit ...
Full textCite
Journal articleIEEE MTT S International Microwave Symposium Digest · September 7, 2011
In this paper, a 3-D Luneburg Lens has been designed, fabricated and characterized. Refractive index control of the lens is based on the mixing ratio of air voids and a polymer. The 12 cm (4λ0 at 10 GHz) diameter lens is designed to work at X-ba ...
Full textCite
Journal articleProceedings of SPIE the International Society for Optical Engineering · July 21, 2011
The DARPA MOSAIC program applies multiscale optical design (shared objective lens and parallel array of microcameras) to the acquisition of high pixel count images. Interestingly, these images present as many challenges as opportunities. The imagery is acq ...
Full textCite
Journal articleFinal Program and Book of Abstracts Iwat 2011 2011 IEEE International Workshop on Antenna Technology Small Antennas Novel Structures and Innovative Metamaterials · June 7, 2011
All dielectric THz waveguide and horn antenna designed utilizing hollow core electromagnetic crystal (EMXT) structures are presented here. Very low loss (0.03 dB / mm) waveguide above 100 GHz has been achieved. Flared horn antenna based on this waveguide h ...
Full textCite
Journal article2011 IEEE 11th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems Sirf 2011 Digest of Papers · March 25, 2011
Various electromagnetic crystal (EMXT) based THz components, including filter/reflector, waveguide, antenna, and transition structure to planar circuits are proposed and simulated. Several of them have been fabricated via a THz rapid prototyping technique, ...
Full textCite
Journal articleOptics express · February 2011
Spectroscopic chemical classification based on adaptive, feature-specific measurements has been implemented and demonstrated to provide significant performance gain over traditional systems. The measurement scheme and the decision model are discussed. A pr ...
Full textCite
Journal articleOptics express · February 2011
An all-dielectric THz waveguide has been designed, fabricated and characterized. The design is based on a hollow-core electromagnetic crystal waveguide, and the fabrication is implemented via polymer-jetting rapid prototyping. Measurements of the waveguide ...
Full textCite
Journal articleOptics Infobase Conference Papers · December 1, 2010
Recent advances in rapid prototyping provide the promise of direct, rapid fabrication of volumetric optical components in the terahertz. We are investigating use of this new technology for fabrication of a Bragg-selective computer-generated volume hologram ...
Cite
Journal articleOptics Infobase Conference Papers · December 1, 2010
Recent advances in rapid prototyping provide the promise of direct, rapid fabrication of volumetric optical components in the terahertz. We are investigating use of this new technology for fabrication of a Bragg-selective computer-generated volume hologram ...
Cite
Journal articleOptics Infobase Conference Papers · December 1, 2010
High-resolution, wide-field-of-view airborne imaging produces large optical systems and data streams. Significant simplification is possible if motion detection, rather than full imaging, is the goal. We consider a static, compressive-sensing architecture ...
Cite
Journal articleOptics Infobase Conference Papers · January 1, 2010
We present an imaging system for target tracking with compressive measurements for large area persistent surveillance. Multiplexed sensing with a mask-based optical system and signal retrieval from underdetermined measurements using l-1 minimization are ex ...
Full textCite
Journal articleJournal of Optics · January 1, 2010
We present a technique to improve the slow-light performance of a side-coupled integrated spaced sequence of resonators (SCISSOR) combined with a stimulated Brillouin scattering (SBS) gain medium in optical fibers. We evaluate device performance of SCISSOR ...
Full textCite
Journal articleProceedings of SPIE the International Society for Optical Engineering · December 1, 2009
Motion tracking in persistent surveillance applications enters an interesting regime when the movers are of a size on the order of the image resolution elements or smaller. In this case, for reasonable scenes, information about the movers is a natively spa ...
Full textCite
Journal articleIEEE Nuclear Science Symposium conference record. Nuclear Science Symposium · October 2009
Advances in 3D rapid-prototyping printers, 3D modeling software, and casting techniques allow for the fabrication of cost-effective, custom components in gamma-ray and x-ray imaging systems. Applications extend to new fabrication methods for custom collima ...
Full textCite
Journal articleProceedings of SPIE the International Society for Optical Engineering · September 8, 2009
Recent advances in rapid prototyping technologies have resulted in build-resolutions that are now on the scales required for direct fabrication of photonic structures in the gigahertz (GHz) and terahertz (THz) regimes. To demonstrate this capability, we ha ...
Full textCite
Journal articleProceedings of SPIE the International Society for Optical Engineering · September 7, 2009
Spectroscopic chemical identification is fundamentally a classification task where sensor measurements are compared to a library of known compounds with the hope of determining an unambiguous match. When the measurement signal-to-noise ratio (SNR) is very ...
Full textCite
Journal articleApplied optics · April 2009
We describe the design and development of an adaptive spectrometer that actively manages dynamic range mismatch between source signals and the spectrometer's detector. The introduction of an inexpensive digital micromirror array yields performance improvem ...
Full textCite
Journal articleOptics Infobase Conference Papers · January 1, 2009
Rapid prototyping technology is now capable of high-resolution fabrication suitable for producing volumetric optics in the GHz/THz range. We will report on our successful fabrication of photonic crystal structures and discuss other components under study. ...
Full textCite
Journal articleOptics express · October 2008
Modern rapid prototyping technologies are now capable of build resolutions that allow direct fabrication of photonic structures in the GHz and THz frequency regimes. To demonstrate this, we have fabricated several structures with 3D electromagnetic bandgap ...
Full textCite
Journal articleOptics express · July 2008
We describe a high-throughput hyperspectral microscope. The system replaces the slit of conventional pushbroom spectral imagers with a static coded aperture mask. We present the theoretical underpinnings of the aperture coded spectral engine and describe t ...
Full textCite
Journal articleOptics express · October 2007
This paper describes a single-shot spectral imaging approach based on the concept of compressive sensing. The primary features of the system design are two dispersive elements, arranged in opposition and surrounding a binary-valued aperture code. In contra ...
Full textCite
Journal articleProceedings of SPIE the International Society for Optical Engineering · August 31, 2007
In this work we develop a spectral imaging system and associated reconstruction methods that have been designed to exploit the theory of compressive sensing. Recent work in this emerging field indicates that when the signal of interest is very sparse (i.e. ...
Full textCite
Journal articleApplied optics · August 2007
We experimentally evaluate diverse static independent column codes in a coded aperture spectrometer. The performance of each code is evaluated based on the signal-to-noise ratio (SNR), defined as the peak value in the spectrum to the standard deviation of ...
Full textCite
Journal articleOptics express · April 2007
We describe a static aperture-coded, dispersive longwave infrared (LWIR) spectrometer that uses a microbolometer array at the detector plane. The two-dimensional aperture code is based on a row-doubled Hadamard mask with transmissive and opaque openings. T ...
Full textCite
Journal articleOptics express · April 2007
We introduce a multiple order coded aperture (MOCA) spectrometer. The MOCA is a system that uses a multiplex hologram and a coded aperture to increase the spectral range and throughput of the system over conventional spectrometers while maintaining spectra ...
Full textCite
Journal articleOptics Infobase Conference Papers · January 1, 2007
We demonstrate a single-shot, dual-disperser spectral imaging system using coded apertures to perform compressive imaging. We also describe associated multiscale reconstruction algorithms to retrieve hyperspectral data from single-shot image. We show simul ...
Full textCite
Journal articleApplied optics · January 2007
We replace the traditional grating used in a dispersive spectrometer with a multiplex holographic grating to increase the spectral range sensed by the instrument. The multiplexed grating allows us to measure three different, overlapping spectral bands on a ...
Full textCite
Journal articleProceedings of SPIE the International Society for Optical Engineering · August 23, 2006
A spectral imager provides a 3-D data cube in which the spatial information (2-D) of the image is comple-mented by spectral information (1-D) about each spatial location. Typically, these systems are operated in a fully-determined (or overdetermined) manne ...
Full textCite
Journal articleProgress in Biomedical Optics and Imaging Proceedings of SPIE · June 29, 2006
We have designed and constructed a multimodal multiplex Raman spectrometer which uses multi-wavelength excitation to better detect signals in the presence of fluorescence by taking advantage of the shift-variance of the Raman signal with respect to excitat ...
Full textCite
Journal articleProceedings of SPIE the International Society for Optical Engineering · May 8, 2006
A hyperspectral imager provides a 3-D data cube in which the spatial information (2-D) of the image is complemented by spectral information (1-D) about each spatial location. A static, high-throughput spectrometer design previously developed by our group c ...
Full textCite
Journal articleApplied Spectroscopy · 2006
Coded aperture spectroscopy allows for sources of large etendue to be efficiently coupled into dispersive spectrometers by replacing the traditional input slit with a patterned mask. We describe a coded aperture spectrometer optimized for Raman spectroscop ...
Full textLink to itemCite
Journal articleProceedings of SPIE - The International Society for Optical Engineering · 2006
We consider compressive sensing in the context of optical spectroscopy. With compressive sensing, the ratio between the number of measurements and the number of estimated values is less than one, without compromising the fidelity in estimation. A compressi ...
Full textLink to itemCite
Journal articleApplied Optics · 2006
We propose a new class of aperture-coded spectrometer that is optimized for the spectral characterization of diffuse sources. The instrument achieves high throughput and high spectral resolution by replacing the slit of conventional dispersive spectrometer ...
Full textLink to itemCite
Journal articleOptics Infobase Conference Papers · January 1, 2005
We describe a hyperspectral imager combining coded aperture spectroscopy and tomographic spatial reconstruction. The throughput of the system is improved compared to scanning techniques while avoiding the missing-cone problem common to many spectral tomogr ...
Full textCite
Journal articleOptics InfoBase Conference Papers · January 1, 2005
Raman spectroscopy in bio-materials is complicated by fluorescence and scattering. We have developed a multimodal, multiplex spectrometer that overcomes these difficulties. We are currently constructing a second generation prototype for in-vivo Raman spect ...
Cite
Journal articleProceedings of SPIE - The International Society for Optical Engineering · 2005
We have developed a class of aperture coding schemes for Remote Raman Spectrometers (RRS) that remove the traditional trade-off between throughput and spectral resolution. As a result, the size of the remote interrogation region can be driven by operationa ...
Full textLink to itemCite
Journal articleProceedings of SPIE - The International Society for Optical Engineering · 2005
We have developed a class of aperture coding schemes for Remote Raman Spectrometers (RRS) that remove the traditional trade-off between throughput and spectral resolution. As a result, the size of the remote interrogation region can be driven by operationa ...
Full textLink to itemCite
Journal articleOptics express · December 2004
We describe a method for efficiently determining the wavelength of a monochromatic source and provide an experimental proof-of-concept. The photomeasurement efficiency for a wavemeter can be written as eta(N,q) = (1 + logqN)/m, where N is the number of spe ...
Full textCite
Journal articlePhysical review letters · April 2004
We observe collective oscillations of a trapped, degenerate Fermi gas of 6Li atoms at a magnetic field just above a Feshbach resonance, where the two-body physics does not support a bound state. The gas exhibits a radial breathing mode at a frequency of 28 ...
Full textCite
Journal articlePhysical Review A Atomic Molecular and Optical Physics · January 1, 2003
A strongly attractive, two-component Fermi gas of atoms exhibits universal behavior and should be mechanically stable as a consequence of the quantum-mechanical requirement of unitarity. This requirement limits the maximum attractive force to a value small ...
Full textCite
Journal articlePhysical Review A Atomic Molecular and Optical Physics · January 1, 2003
We derive the elastic collision rate for a harmonically trapped Fermi gas in the extreme unitarity limit where the s-wave scattering cross section is [Formula Presented] with [Formula Presented] the relative momentum. The collision rate is given in the for ...
Full textCite
Journal articleScience (New York, N.Y.) · December 2002
We report on the observation of a highly degenerate, strongly interacting Fermi gas of atoms. Fermionic lithium-6 atoms in an optical trap are evaporatively cooled to degeneracy using a magnetic field to induce strong, resonant interactions. Upon abruptly ...
Full textCite
Journal articlePhysical review letters · March 2002
We achieve degeneracy in a mixture of the two lowest hyperfine states of 6Li by direct evaporation in a CO2 laser trap, yielding the first all optically produced degenerate Fermi gas. More than 10(5) atoms are confined at temperatures below 4 microK at ful ...
Full textCite
Journal articlePhysical Review A Atomic Molecular and Optical Physics · January 1, 2002
We measure a zero crossing in the scattering length of a mixture of the two lowest hyperfine states of [Formula Presented] To locate the zero crossing, we monitor the decrease in temperature and atom number arising from evaporation in a [Formula Presented] ...
Full textCite
Journal articleConference on Quantum Electronics and Laser Science QELS Technical Digest Series · January 1, 2002
Degenerate two-component Fermi gases offer possibilities for precision studies of pairing interactions in systems for which the density, temperature, and interaction strength are widely available. Of particular interest are the two-component mixtures of
Cite
Journal articlePhysical Review A Atomic Molecular and Optical Physics · January 1, 2001
The spatial loading dynamics of a carbon dioxide (CO2) laser trap and the equilibrium number of trapped atoms are described using Fokker-Planck model. The absorption of the magneto-optical trap (MOT) beams in the high density region of the (CO
Cite
Journal articlePhysical review letters · September 2000
We use an all-optical trap to confine a strongly attractive two-state mixture of lithium fermions. By measuring the rate of evaporation from the trap, we determine the effective elastic scattering cross section 4pia(2) to show that the magnitude of the sca ...
Full textCite
Journal articlePhysical Review Letters · January 1, 1999
We demonstrate an ultrastable CO2laser trap that provides tight confinement of neutral atoms with negligible optical scattering and minimal laser-noise-induced heating. Using this method, fermionic6Li atoms are stored in a 0.4 mK deep ...
Full textCite